I would like to ask why permissions are not on the same tab? "Can permanently delete own posts" is on "Post" tab and "Can soft delete own posts...." is on "Misc" tab. Wouldn't be easier for administrators to put them together?

I tested this feature a little and I have a few questions. Maybe I miss something here.

First example:
I created test user and gave him permission for permanent and soft delete of his own posts.
Test user wrote post and try to delete it. It shows him, that he can "Delete permanently", so he tick it and confirm it. The post si deleted for the test user, but I (with moderator permissions) still can display the post and restore it.

Another example:
Same permissions, user and post as before, but user decided to soft delete the post (he didn't tick "Delete permanently" and wrote "Soft delete reason"). After he soft deleted it he cannot see the post or link to display it, but I as moderator can display it and restore it

Questions are:
What is point to let user to decide how to delete the post if in first example the post isn't permanently deleted and in second example the post is soft deleted, but he can't to restore it? I mean whatever user choose it will end the same.
Shouldn't be in the first case the post deleted permanently, so no moderator can restore it?
Shouldn't be user able to restore the soft deleted post himself? (without "approve posts permission" for moderators)

All the permissions necessary for the feature to work are not created when upgrading a phpBB 3.0.12 forum to phpBB 3.1. Ticket created, see PHPBB3-13270. In particular there are no records in the acl_roles_data table to give permission (m_softdelete) to moderator roles.

Yes we are aware. For future reference please keep in mind that bumping an RFC topic on here to report an issue doesn't really accomplish anything. If there is a ticket already then we know about it. If there isn't a ticket then you should create one to correct such bugs. If you have additional information regarding the bug then that goes in the ticket.